My ex MOD 109

It’s a 1982 ex MOD 109. I have the military plate with the military registration on but haven’t got round to tracing it’s military history through Gaydon, I will get on to it some time.

The truck left service with it’s chassis in pristine condition and a previous owner had it galvanised. It’s very unusual to find an original MOD chassis that has been galvanised and it  benefits from the removable gearbox cross member, this means the gearbox can be dropped to the floor rather then up through the cab, which is a pain the arse as the floor needs to come up and the seat box has to come out..

When I bought the landy in Jan 2007 it had a petrol 2.25 engine that also had a single point LPG system with a 100 litre tank behind the rear bulkhead. With this set up it averaged 14 mpg. It ran very well on LPG and I would recommend the conversion to anyone. I found that LPG preferred the timing to be slightly advanced so I set the timing for optimum running on LPG, as a result it ran a bit rough on petrol.  Some people set the timing somewhere between the two but in my opinion going it that way you’re are getting the best of neither fuel. As a result I never used petrol, only in an emergency when I ran out of LPG and this was rarely. The truck started on LPG in all weathers with out any problems, the engine oil remained clean, and after another 20k miles when I split the engine to sell the cylinder head, it was in still in perfect condition.

A couple of years ago I picked up a low mileage (85k) Defender 200TDI engine with LT77 gearbox for the bargain price of £500 so decided to drop the TDI into the 109 with the standard series gearbox. This has been the set up until now and it gets 30mpg round town and up to 36mpg on a run but with the added bonus of LOADS more power!!

Cracked piston.

Not long after I bought the Land Rover, when I still had the 2.25 petrol engine, I had a problem with excessive blue smoke, mainly after the engine had been idling for any amount of time. There’d be a significant amount of smoke which would clear as I drove off. I pulled the plugs and got the following result:

Spark plugs oily residue

I thought it must be worn valve stem seals or a badly worn valve guide on no.3 cylinder due to that plug being so oiled up. The engine was also now starting to miss on no.3 due to the contamination of the spark plug. Compression test showed no unusual figures.

So I removed the head and had it crack tested, no cracks. I cleaned up the head and new genuine valve seals were installed (I bought Britpart first but the quality was very poor). I managed to replace the valve guides by using the drifts sold by Dingocroft (these are copies of Landrover special tools RO274400 for the inlet, can’t find the part number for the exhaust guide drift). I heated up the cylinder head on the stove and froze the guides for a couple of days before installing as they are obviously a very tight interference fit.

I also ported the head a little using a dremel, the 2.25 heads are quite rough and have a lot of casting imperfections that can be taken out, resulting in smoother running and a little more power.

Anyway, I replaced the head and the engine ran much smoother however the smoke was still there. Lots of head scratching ensued…so head off again. This time I cleaned the carbon off the tops of the pistons (doh I know…) and found a great big crack across no.3 that was not originally visible under the carbon:

Cracked Piston

I have no idea how it happened, the engine had genuine low miles at 39k. Can only think it must’ve been something to do with the previous owner using the landy to launch boats and some water had got in the intake. The other pistons weren’t great and were showing signs of similar wear so I bought a new set of AE from Dunsfold for £100 and installed them with new big end shells. Along with the work I’d done on the head, the engine ran beautifully for years on LPG up until I replaced it with a 200TDI.